The “quick start” button on an exercise machine, which usually gets the gears moving at a consistent pace, is known to be the least effective setting. Study afterstudy shows that doing interval workouts can not only help you get fitter faster but can also encourage your body to burn more fat after the workout is finished. “We’ve found that when people do the same steady-state routine every time they get on the machine, they plateau both physiologically and mentally,” says a representative from Precor, a company that makes premium fitness equipment. That’s why newly designed Precor elliptical machines for gyms and, more recently, homes eliminate or make it harder to find the “quick start” feature and instead highlight interval options with varying levels of intensity. (You can find these interval workouts on any type of exercise machine.)

2

Mistake: You exercise now so that you’ll have Madonna’s stamina (and maybe her arms) when you’re her age.

Research from Michelle Segar, PhD, a behavioral sustainability expert at the University of Michigan, found people want to age well—in theory—but when Segar has followed up with exercisers over time, those who felt they got noticeable (and immediate) rewards from their workouts exercised 20 percent more than those who said that their goal was to stay healthy. If you focus on the feel-good endorphins or stress relief you notice as soon as the class is over, you’ll be more likely to schedule another workout ASAP.

3

Mistake: You think you’re working your butt off in hot yoga class.

Turning the temperature up in the yoga studio doesn’t actually make us work any harder, found researchers at the American Council on Exercise. Although the hot yogis were soaked with sweat and rated their workout as totally killer, the data showed that there was no real difference in their core temperature or heart rate. In fact, both classes would be classified as “light” exercise, based on industry guidelines. Yoga in all forms still provides amazing psychological and physical benefits, and the same ACE study concluded that these types of hot workouts are safe, so keep it up (just add a high-intensity workout into your schedule, as well).

4

Mistake: You wear your “indoor sneakers” to indoor cycling class.

The only pair of you shoes you should be wearing on the bike are bike shoes, because they’ll not only prevent injury but also help you work harder and use more muscle groups. Cycling-specific shoes have a hard, rigid sole and clips that attach to the pedals. This improves stability and reduces pressure on the bottom of the foot. And unlike soft-bottomed sneakers, clipped-in cycling shoes allow you to pull up through the pedal stroke, so that you work not only your quads but also your glutes and hamstrings, says Janet Fitzgerald, an indoor-cycling veteran and a master instructor and trainer for SoulCycle. Yes, the shoes are an added expense, but you’ll really feel—and see—the difference.

5

Mistake: You stretch to limber up.

Research shows that static stretches, like the classic toe touch, reduce strength in the stretched muscles by almost 5.5 percent, with the impact increasing in people who hold the pose for 90 seconds or more. Other studies have shown that pre-workout static stretching can make jumpers less powerful, sprinters less fast, weight-lifters less steady and all athletes more vulnerable to injury. You’re much better off with a dynamic warm-up, in which you perform moves that mimic the activity you’re about to engage in (think Michael Phelps–style arm swings before swimming laps).

6

Mistake: You proactively pop anti-inflammatories.

We know many athletes — even some doctors — who used to take ibuprofen tablets before a workout to protect against inflammation. The idea was that if you didn’t feel the pain, you could muscle through it. This practice is now strongly discouraged, after studies revealed that anti-inflammatories may have potentially hazardous effects on the GI system during strenuous physical activity. Over the long term, chronic pill-popping can lead to serious GI issues that involve small amounts of bacteria and digestive enzymes leaking into the bloodstream. What’s more, the pills might even affect muscle recovery in the hours after a workout.

7

Mistake: You always get up at the crack of dawn to work out.

It’s important to find time to exercise, but not at the expense of sleep. A sleep deficit will make you feel groggy and leaden, and getting extra sleep will even give you an extra edge. Stanford University sleep researchers have shown this time and again with swimmers, tennis players and basketball players: In each experiment, increasing sleep time significantly improved the athletes’ performance in areas like hand-eye coordination, reaction time, speed and power. If getting to bed early just isn’t an option, do what you can to schedule naps before a competition or a hard workout session.